JULY 1957
ELEMENTARY PARTICLES — “In the strangeness theory, then, we have a means of classifying strange particles. The theory is consistent with the fundamental idea of four groups of particles and three types of reactions. At present our level of understanding is about that of Mendeleyev, who discovered only that certain regularities in the properties of the elements existed. What we aim for is the kind of understanding achieved by Pauli, whose exclusion principle showed why these regularities were there, and by the inventors of quantum mechanics, who made possible exact and detailed predictions about atomic systems. We should like to know the laws of motion of the particles; to predict, among other things, how they will interact when they collide and how these interactions will deflect one particle when it collides with another.—Murray Gell-Mann and E. P. Rosenbaum”